An elderly man has died at a Nelson beach, despite attempts to rescue him.

A police spokeswoman said the man in his 70s was swimming at Tahunanui Beach about 7.30pm last night when he got into difficulty. He died at the scene.

The spokeswoman said a member of the public attempted to rescue the man but was unsuccessful. The man's family were being advised of his death.

Nelson police Sergeant Adrian Cupit told Fairfax the member of the public did a "fantastic job" performing CPR, but it was to no avail.